Re: cp --reflink with Btrfs

Andreas Barth
2010-01-27T10:53:22Z

* Sage Weil (sage@newdream.net) [091216 17:55]:
> On Wed, 16 Dec 2009, Li Dongyang wrote:
>
> > Have a look at line 998, ioctl.c, inside btrfs_ioctl_clone(),
> > the src->i_size(the size of the testfile created by touch) is just 0, and this
> > will cause btrfs_ioctl_clone just return -EINVAL.
> > I'm not sure if it makes sense to clone a file which actually doesn't have any
> > data extents.
>
> Probably not, but it seems more consistent to return success instead than
> -EINVAL. Requiring the caller to check and special case empty files isn't
> very friendly...

Actually it makes lots of sense if trying to e.g. cow-copy an chroot
on an buildd, and there are some empty files inside of the linux
installation (which normally just are).

Can I hope on getting the patch (or another patch) incorporated into
the kernel?

Cheers,
Andi